This invention relates to a closure mechanism and more particularly, but not exclusively to a shutter mechanism for a camera.
According to the present invention there is provided a closure mechanism in which a closure member is mounted for movement relative to an aperture and in which means are provided for moving the closure member to cause it to roll on a support member thereby to cause a part of the closure member to move across the aperture to form a movable barrier providing selective communication of the aperture with spaces on opposite sides of the closure member.
Preferably, the closure member has an arcuate portion with a generally curved face, which rolls on a generally flat, face of a support portion of the support member. Where the curved face is generally part cylindrical, the said part of the closure member is at the axis thereof and moves across the aperture in a straight path extending substantially transverse that axis.
The closure member may comprise a part-cylindrical portion and a substantially flat portion extending radially from an edge of the cylindrical portion to the axis thereof, where means are provided to form a seal between the closure member and a flat surface of, or surrounding the aperture.
The closure member may be a shutter in a camera, the aperture comprising an optical element, for instance a fibre optic face plate, through which images may be transmitted. On one side of the shutter may be a viewing system for viewing the image passing through the optical element and on the other side may be a film locating and transport system, the shutter being mounted in an enclosure which is open on opposing sides to said viewing, and said film locating and transport systems. To provide positive engagement for proper rolling of the shutter in the enclosure without slip between the shutter and the support member, the curved surface of the former may be provided with elongate axially extending teeth which mesh with teeth provided on an inner surface of a wall of the enclosure, this wall constituting the support member. The flat portion of the shutter is preferably provided with a mirror which forms part of the viewing system and which in one extreme position of the shutter lies on and oblique to the optical axis through the optical element thereby to reflect light passing therethrough to the other elements of the viewing system.